Evolution of Glucose Aversion Cockroaches

German Cockroach Head taken by 

Ayako Wada-Katsumata and Andrew Ernst

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Researchers, Ayako Wada-Katsumata, Jules Silverman, and Coby Schal, found that some German cockroaches have developed an adaptive behavior of glucose aversion. Glucose, a simple sugar, is used to cover the poison in man-made traps for cockroaches. The German cockroach has gustatory receptor neurons (basically taste buds) in their mouths. The researchers focused on the sweet and bitter gustatory receptor neurons. When the glucose aversion cockroaches were expose to fructose, another type of simple sugar, the sweet gustatory receptor neurons were activated. Activation of the sweet gustatory receptor neuron means that the cockroach will continue eating. However, when the glucose aversion cockroach was expose to glucose, the bitter gustatory receptor neuron were activated. The activation of the bitter gustatory receptor neuron causes the cockroach to stop feeding. The mutation of the glucose aversion German cockroach has helped the cockroaches evade human termination, which allows the glucose aversion German cockroach to pass on the mutation to their offspring. The evolution of the glucose aversion German cockroach is quite interesting because of its advantage in the outmaneuvering man-made traps. The original article can be found here on Science's website. ​

Bdelloid rotifers' Horizontal Gene Transfer Ability

Bdelloid rotifer Macrotrachela quadricornifera image by Diego Fontaneto and Giulio Melone

A recent article states that the asexual reproducing organism, Bdelloid rotifer have the ability to engage in horizontal gene transfers (as oppose to vertical gene transfers which arise from  human parents to their human offspring) with eubacteria, algae, protists, and fungi. It is thought that the main benefit of asexual reproduction is that the organism is surviving in a constant environment. However, the genetic diversity found in Bdelloid rotifer exceeds that of what should arise in asexual reproduction. It was previously thought that the Bdelloid rotifer mutates its genome significantly enough so it can acquire special traits like withstanding extreme desiccation. This new research overturns current thought that asexual reproducing organism are less likely to endure evolutionary changes than sexually reproducing organisms.

Original research article by C. Boschetti, A. Carr, A. Crisp, I. Eyres, Y. Wang-Koh, E. Lubzens, T. Barraclough, G. Micklem, and A. Tunnacliffe (2012) published on PLOS Genetics can be found here.